How
Does the Ear Work?
The ear is divided into three sections: the
outer ear, middle ear, and inner ear (Figure 1).
The outer ear is the
portion of the ear you can
see plus the ear canal that leads down to the
eardrum (tympanic membrane). The middle
ear begins at the eardrum and includes three
small bones. Together, the three bones are
called the ossicles. The three middle ear
bones are called the malleus (or hammer),
the incus (or anvil) and the stapes (or stirrup).
Sound waves travel down the ear canal
and cause the eardrum to vibrate. The vibrations
move the middle ear bones that in turn push a
membrane. Behind the membrane is the fluid
in the inner ear. The inner ear consists of both
balance and hearing components.
The hearing component is called the cochlea.
The movement of the inner ear fluid in the cochlea
results in electrical signals.
These signals are sent to the hearing nerve
and brain and we hear sound.
Types
of Hearing Loss
There are three types of hearing loss: conductive, sensorineural and mixed loss.
Conductive Hearing Loss
Hearing loss that is caused by the damage to the outer or middle ear regions is called conductive hearing loss. This type of hearing loss attenuates
sound, meaning everything sounds much quieter than normal. Conductive hearing loss is usually medically or surgically treatable.
Sensorineural Hearing Loss
Hearing loss caused by damage to the inner ear region or the auditory nerve (also called the hearing nerve) is called sensorineural hearing loss (more commonly known as nerve deafness). This type of hearing loss results in sounds being softer than they really are and is associated with distorted sound quality. Individuals with this type of hearing loss often complain of the impaired ability to hear and understand speech. There are many different causes for this type of hearing loss, including exposure to loud sounds, music or noise; or as a result of the aging process. The standard treatment for sensorineural hearing loss is the use of hearing aids.
Mixed Hearing Loss
Hearing loss that includes both sensorineural and conductive components.
Effectiveness
of Traditional Hearing Aids
Individuals with a moderate to severe sensorineural hearing loss are often not happy with the benefit received from traditional hearing aids. In a survey of 3000 hearing aid wearers it was found that:
• 65% of respondents desired better sound quality in the category of speech in a noisy environment.
• 66% sought improved relief from the whistling and buzzing of the hearing aids.
• 57 and 58% asked that the sound quality in soft and loud sounds respectively be improved upon.
• 52% said a better fit and comfort needed improvement.
Courtesy of MarkeTrak VI report by Sergei Kochkin, The Hearing Review; Nov. 2002.
